I have my dash removed and trying to get my fan to work on more than just high. I followed the wiring to the firewall and it is cut just in side the engine bay. What I am I missing to get the fan to work on all speeds?

The car was an a/c car but the a/c has been removed. the wires are in the engine bay are green (light green), black/blue, blue, black /yellow, and black /brown. Only the black/brown is still attached and appears to go to the heater rely.

I tested the fan switcth and the blue wire has power on 1st, the black/blue on 2nd, and the black/yellow on 3rd. Assume the black/brown is causing the fan to work on high.

Thanks

 

You need the heater resistor board. There was one on eBay. one wire to each terminal gives you each speed... Hot wire to the common terminal on the resistor board. Schematic available on Wild about cars dot com A/C cars had the board mounted to the heater case under the hood and non A/C cars had the board mounted on top of the heater case under the dash to the right of centre, about the height of the radio.

 

Yes, you're missing the resistor block which is screwed to the A/C air duct, which is what someone removed from your car.

Be sure to thank them when you see them.

- Eric

 

He's also missing the A/C harness that is the part that's cut in his first post. That's what plugs into the resistor.

FYI, Scott's wiring was hacked by a P.O. and he's been struggling to get the dash wiring sorted for a while now.

 

I looked on www.wildaboutcarsonline.com and did not find the wiring diagram. I guess that is what I need at this time. I have lost my manual. Going to have to find or purchase a new one.

No sure if going from an a/c car to removing the a/c will have to do with it.

 

Might have answer my own question.
http://www.opgi.com/cutlass/1972/ign...-wiring/16690/
Is this what I need? Starting from the center and going counter clockwise, the center 5 connectors, connect to the HVAC control in the dash. Then at the first junction (10 oclock 2nd loop in the photo) exits the interior to the engine bay (this is where mine is cut). Continuing counter clockwise the 3 connectors attached to the heater rely next to the brake booster. Then going clockwise from the junction, the gray connector connects to the engine wiring harness and the purple wire to the fan with the remaining connector unused as they are for the a.c.

That or I need to know what is going on behind the wiring looms.

 

You could spend $122, or you could just splice on a few wires. Your choice.

The diagram for the A/C wiring is in the A/C section, not the Electrical section.

The diagram is in black and white, but all of the colors are clearly indicated.

- Eric

 

I have a NON ac car with a similar condition. Fan only works on high speed. Are you guys saying this is the resistor that's no good? I originally thought it might just be the dash switch. My harness is original (except for aftermarket stereo right now) so for the most part completely intact.

 

Could be either one.
Easy enough to check with the diagram and a meter or test light.

Mr. Hoffman, here are those diagrams from the CSM:







- Eric

 

thanks for the assistance. I could not find that diagram. I found the one in the service manual but it did not give wiring colors. I will see what my car has in it tonight and order the parts I need.

 

Interesting, the resistor is on the cabin side of the firewall in a Heater only equipped car. Just a little bit awkward to get to, but not impossible. I have several new switches so I might just plug one in first to see if that solves anything. If not I guess I'll have to get the resistor rebuilt unless you guys know where new aftermarket ones are available.

 

OPGI sells them and I think Rockauto

 

Couldn't find it at RA. The OPGI and Supercars Unlimited resistor is 4 prong for AC and much more expensive


I Found the 3 prong at Parts place for 24.00 and Year One for 20.00. I think I need to check mine first and see if it's the problem and also how many contacts it has. Sorry for the jack on this thread.